Internal combustion engine



y 6 A. 5. KING 3,249,097

INTERNAL COMBUSTION ENGINE /7&

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Wimp 5. Km;

y 3, 1966 A. 5 KING 3,249,097

INTERNAL COMBUSTION ENGINE Original Filed Jan. 15, 1962 2 Sheets-Sheet 2INVENTOR. Arr/um 5. KM;

United States Patent 3,249,097 INTERNAL COMBUSTION ENGINE Arthur S.King, 6836 Fontana, Prairie Village, Kans. Original application Jan. 15,1962, Ser. No. 166,308, now Patent No. 3,172,596, dated Mar. 9, 1965.Divided and this application Feb. 18, 1965, Ser. No. 433,815 Claims.(Cl. 12369) This is a division of my copending application Serial No.166,308, filed January 15, 1962, and entitled, Free Piston EngineCompressor, now Patent No. 3,172,596, granted March 9, 1965.

This invention relates to fluid compressors and, more particularly, toan engine compressor of the free-piston type.

It is well known to use a two-cycle internal combustion engine incombination with a piston-type compressor for use in refrigerationsystems or the like. Heretofore, such engine compressors have beensubject to certain characteristic limitations so that their use has notbeen widespread. In addition to certain limitations inherent inconventional two-cycle engines, the increased sealing problemsencountered in previous engine compressor assemblies usually resulted inloss of fluid, often expensive refrigerant fluids, from the compressorunit. Additionally,-products of combustion have escaped from thecylinder of the engine into the compressor where they contaminated theother fluids.

Accordingly, it is the most important object of my invention to providean improved engine compressor assembly having means to prevent the lossfrom the system of whatever fluids manage to escape from the compressorunit during the compressing operation.

Still another object of this invention is the provision of an improvedinternal combustion engine for use in an engine compressor assemblycapable of more efficient operation than with heretofore known enginesand adaptable to either gas or carburetor fuels so that operation of theassembly is feasible for a wide range of uses.

Another object of my instant invention is the provision of a free-pistonengine compressor assembly utilizing spring means for returning thepower piston to top deadcenter position for obviating the use ofso-called bounce cylinders and pistons, commonly thought necessary forthis purpose, thus avoiding the inevitable problem of fluids leakingpast the seals of such bounce cylinders.

A further object of the present invention is the provision for use withsuch an assembly, of a reciprocating magneto operably coupled with amake-and-break vibrator so that adequate spark is furnished for startingthe engine, automatically followed by time-d ignition for smoothoperation when the engine has started cycling.

Yet another object of this instant invention is the provision ofimproved lubricating and sealing means for preventing the escape ofproducts of combustion and other fluids from within the combustionchamber to other components of the assembly, thereby insuring that suchwaste materials are properly exhausted to the atmosphere to render aninternal combustion engine safe for extended operation with very littleoperator attention.

In the drawings: 7

FIGURE 1 is a top plan view of the engine compressor assembly embodyingthe principles of the invention, parts being broken away to revealdetails of construction;

FIG. 2 is a cross-sectional view taken along line 22 of FIG. 1, with thebattery, starting button, and fuel pump motor shown schematically; and

FIG. 3 is a fragmentary, cross-sectional view taken along line 3-3 ofFIG. 1.

Briefly, this invention relates to a free-piston engine compressorassembly wherein a twocycle, free-piston,

3,249,097 Patented May 3, 1966 "ice internal combustion engine has arigid, reciprocable work shaft adapted to be coupled to a reciprocablecompressing member of a compressor unit. The engine is provided with apiston pump driven by an electric motor for providing the necessary fuelcompression for starting the 7 engine. Star-ting ignition is initiatedby a make-and-break vibration which induces an electrical current in thesecondary windings of an induction coil, the latter being operablycoupled with a reciprocating magneto to automatically provide timedignition after the engine has commenced running.

A secondary piston reciprocated by the work shaft forces fuel into thecombustion chamber, and a springbiased valve withholds the injection offuel until a predetermined fuel pressure is reached. A coil spring isused to return the engine piston to top dead-center position, thuseliminating the need for a conventional bounce piston. Novel means isprovided for directing a large volume of compressed air into thecylinder to scavenge the combustion chamber after the fuel supply hasbeen cut off.

An engine compressor assembly broadly designated 10, includes acompressor unit 12 and prime mover means for the compressor in the formof a two-cycle internal combustion engine 14. Engine 14 is of thefree-piston type and is provided with a cylinder 16 defining acombustion chamber 18 in which is received a power piston 20 forreciprocation in cylinder 16. The latter is closed at one end by headwall 22 and at the opposite end by a relatively thick base plate 24.

Cylinder 16 is provided on the external surface thereof with theconventional fins 26 for cooling engine 14. Piston 28 is provided with adepending, annular skirt 28, and cylinder 16 has an exhaust port 30communicating the interior of cylinder 16 with the atmosphere. Port 30is so disposed intermediate the ends of cylinder 16 to be entirelycovered by skirt 28 during a portion of the reciprocation of piston 20within cylinder 16, and to be uncovered by piston 20 when the latter isreciprocated to a position adjacent plate 24. Seal means 32circumscribes piston 20 in an annular recess 34 to prevent the flow offluid between the outer surface of piston 20 and the inner surface ofcylinder 16 during the reciprocation of piston 20.

Piston 20 is rigidly coupled with a work shaft 36 ex- 7 tending throughplate 24 and into unit 12. Work shaft 36 is rigidly coupled with amember 38 extending in sealing relationship across a drum 40 definingthe compressing chamber of unit 12. The rigid coupling of piston 20 withmember 38 by work shaft 36, insures that member 38 will be reciprocatedwithin drum 40 as piston 20 reciprocates within cylinder 16.

An enclosure 42 in the form of a cylindrical wall, extends between unit12 and engine 14 and defines a compartment 44 which is generally sealedagainst ingress or egress of fluid by rigid coupling to plate 24 and oneend 46 of unit 12. Work shaft 36 passes through the compartment 44 and afirst seal 48 in plate 24 and disposed in surrounding relationship towork shaft 36, operates to prevent the flow of fluid from engine 14 intocompartment 44. To this end, seal 48 includes an annular recess 49adapted to be filled with liquid in a manner to be made clearhereinafter, and a pair of O-ring seals or the like 51 and 53 disposedin circling relationship with respect to work shaft 36 and on eitherside of recess 49 in channels provided in plate 24.

A second seal 50 in end 46 and disposed around work shaft 36, preventsthe escape of fluid from compressor unit 12 into compartment 44.Inasmuch as work shaft 36 reciprocates during the operation of assembly10 and compressor unit 12 contains fluid at relatively high pressures,it is diflicult to absolutely'prevent the passage of any fluid alongreciprocating work shaft 36 and past seal 50. Such leakage, however, iscalculated to be received into compartment 44 for a purpose to behereinafter more fully explained.

Means for delivering fuel into combustion chamber 18 of engine 14,includes a second cylinder 52 within compartment 44 and surrounding workshaft 36. Second cylinder 52 is closed at the upper end thereof by plate24 and has a transversely extending end wall 54 closing the oppositeend.

Work shaft 36 extends through the cavity 56 defined by cylinder 52, anda fluid seal 58 is disposed adjacent wall 54 to prevent the passage offluid from cavity 56 into compartment 44. A second piston 60 is rigidlysecured to work shaft 36 as by key 62 for reciprocation within cylinder52, and has conventional seal means 64 circumscribing piston 60 toprevent the passage of fluid between piston 60 and between cylinder 52and piston 60 as the latter is reciproca ted by work shaft 36.

A passage 66, extending through plate 24, communicates with cavity 56and is adapted to be coupled with a source of fuel for engine 14 byextension 68 bolted to the outer surface of plate 24. A check valve 70is disposed in extension 68 between the source of fuel and passage 66 topermit the passage of fuel from the source to cavity 56 and to precludeflow in the opposite direction.

A second passage 72 in plate 24, is in fluid communication with cavity56 and a conduit 74 secured to the outer surface of plate 24 andextending to a tank 76 situated above cylinder 16 and secured to headwall 22 of the latter. A second check valve 78 is disposed adjacent thedischarge opening of conduit 74 within tank 76 to permit fluid to flowinto the latter and to prevent the return flow thereof from tank 76 inthe direction of cavity 56. Control means 80, comprising a valve 82biased by a coil spring 84 into closing disposition across a passage 86communicating tank 76 with combustion chamber 18 of cylinder 16,prevents the flow of fuel from tank 76 into combustion chamber 18 untilthe fuel reaches a predetermined pressure.

A cylinder 88 integral with tank 76, and in fluid communicationtherewith, has a small piston 90 disposed therein to prevent the flow offluid out of tank 76 through cylinder 88. Piston 90 is operably coupledwith an eccentric 92 by piston rod 94 and eccentric 92 is coupled withmotor 96 through worm gears 98 whereby rotation of eccentric 92 by motor96, reciprocates piston 90 within cylinder 88 'for a purpose to beexplained later.

A coil spring 100 is disposed between the upper surface of plate 24 andthe bottom surface of piston 20 to bias the latter toward its topdead-center position after piston 20 has been driven toward a positionadjacent plate 24 by the combustion of the fuel within combustionchamber 18.

A liquid-containing vessel 102, disposed in surrounding relationship towork shaft 36, and having its bottom end closed by plate 24 and theupper end thereof constricted and provided with a fluid seal 104 influid-sealing relationship to reciprocating work shaft 36, communicateswith a liquid supply tank 106 positioned outside of cylinder 16. Passage108 extending through plate 24, provides the means for communicatingtank 106 with vessel 102.

Plunger means 110 comprising a piston 112 in tank 106, and a spring 114,urges the liquid within tank 106 through passage 108 and into vessel 102for a purpose to be later described. A channel 116 extendinglongitudinally through the upper portion of work shaft 36, is placed influid communication with the inside of vessel 102 by laterally extendingports 118 so located in work shaft 36 to be disposed within vessel 102throughout the entire reciprocation of work shaft 36 during operation ofengine 14. Channel 116 communicates with a canal 120 extending radiallyoutwardly in piston 20 and communicating with recess 34 in the outersurface of piston 20.

Thus, the urging of the liquid into vessel 102 by plunger means furtherurges the liquid into channel 116 where it is distributed to recess 34by canal for the lubricating of the outer surface of piston 20.

The inside of cylinder 16 is placed in fluid communication withtheatmosphere by a late-rally extending port 122 and an extension 124provided with a check valve 126 which permits the passage of air intocylinder 16, but prevents the flow of air in the opposite direction.Port 122 is disposed adjacent plate 24 at the bottom of cylinder 16 in aposition not to be covered by skirt 28 of piston 20 throughoutsubstantially the entire reciprocation of the latter. Means is providedfor conducting the air which enters cylinder 16 beneath piston 20, intothe combustion chamber 18 above piston 20. Such means is in the form ofa block 128 integral with the outer surface of cylinder 16 and havingapassage 130 in fluid communication with the inside of cylinder 16adjacent plate 24" Ma port 132. Passage 130 also communicates withcombustion chamber 18 through a port 134 disposed in vertically spacedrelationship with respect to plate 24 and in a position to be cleared bypiston 20Iwhen the latter is reciprocated to a position adjacent plate24. Port 134 is disposed in opposed relationship with respect to exhaustport 30, and port 132 is disposed in opposed relationship with airintake port 122.

Additional means for pumping air into cylinder 16, comprises a conduit136 communicating with second cylinder 52 through an opening 138 in endWall 54, and with air intake port 1220f engine 14. As piston20 andsecond piston 60 are reciprocated to their uppermost positions, checkvalve 126 is opened to permit air to flow into engine 14 through port122 as will be more fully explained later. Inasmuch as conduit 136 is influid communication with port 122, air is sucked into second cylinder 52by the upward reciprocation of piston 60. Thus, cavity 56 beneath piston60, is filledwith :air at the time that the pistons are in their upperpositions as illustrate-d in FIG. 2.

Ignition means for causing the combustion of the fuel within engine 14comprises a spark plug 140 electrically coupled with means forenergizing the same. Such energizing means includes components forenergization when engine 14 is initially being started and othercomponents for producing timed ignition. after engine 14 has startedrunning. The starting components comprise electrically responsiveinduction apparatus 142 in the form of a conventional make-and-breakvibrator having a spring 144 provided with an electrical contact 146 andassociated with a vibrator spring 148 having an electrical contact 150.

Spring 144 is electrically coupled with one pole of a suitable source ofelectrical energy which may be in the form of a battery 152, by line 154shown in FIG. 2. The other side of battery 152 is electrically coupledwith a single-pole single-throw switch 156' by line 158. The other poleof switch 156 is grounded to assembly 10 by line 160 which is connectedto an outwardly extending cooling fin 162 which is provided on the outersurface of enclosure 42. The connection between line 160 and fin 162may: be by soldering or the like. Lines 154 and 160 are coupled to motor96 by lines 164 and 166 respectively to place motor 96in parallel,electrical connection across battery 152.

Spring 144 of apparatus 142 is insulated from a mounting bolt 143, butspring 148 is electrically coupled with bolt 143. The latter isinsulated from enclosure 42 by a block 145 and a washer 147ofinsulatingmaterial. Bolt 143 is electrically coupled with the primarywindings of an induction coil 168.by line and lead 172. Thus, whenswitch 156 is depressed, a circuit is completed to energize motor 96traced frombattery 152, line 158, switch 156, line 166, motor 96, line164 to the other side of battery 152. As previously described, one endof induction coil 168 is coupled to lead 172. The outer end of theprimary windings of coil 168 is electrically coupled with enclosure 42as by soldering or the like, not shown.

Thus, when switch 156 is closed, a circuit energizing coil 168 may betraced through battery 152, switch 156, line 160, enclosure 42, primarywindings of coil 168, lead 172, line 170, bolt 143, spring 148, contact150, contact 146, spring 144, line 154 to the other side of battery 152.An extension 174 integral with the outer end of spring 148 is disposedadjacent a core 176 operably associated with induction coil 168, wherebyextension 174 is attracted toward core 176 as the latter is magnetizedthrough the passage of electricity through the primary windings of coil168. Contacts 150 and 146 are so disposed in opposing relationship thatthey are normally connected, but may be separated as core 176 attractsextension 174 of spring 148.

It will be readily understood, of course, that the secondary windings ofcoil 168 are grounded at one end by connection to closure 42, and theother end thereof is electrically coupled with spark plug 140 byignition wire 178 shown but fragmentarily in the drawings.

A magneto provides the necessary ignition for the operation of engine 14after the latter has started cycling. To this end, a permanent magnet180 is releasably se- "cured to shaft 36 for reciprocation by the latterand may be adjustably positioned at a predetermined location along thelongitudinal length of work shaft 36 by setscrew 182.

Mechanism 184 comprising a fixed contact 186 rigidly mounted in the sidewall of enclosure '42 and insulated from the latter by a block 188 ofinsulating material, is externally threaded and kerfed at one end sothat contact 186 may be moved inwardly or outwardly by turning thelatter with a screwdriver or the like. A generally L-shaped, movablecontact 190 is pivotally coupled to a bracket 192 rigidly secured to theinside of enclosure 42 adjacent fixed contact 186, and is biased byspring 194 so that a projection 196 integral with contact 190 isnormally in engagement with the inner end of fixed contact 186.

Bracket 192 is constructed of electrically conductive material,' as ismovable contact 190, and the pivotal 'coupling'of the latter to bracket192 permits the electrical'connection between the bracket'192 andcontact 190 at all times. A leg 198 of contact 190 extends laterallyinwardly from the point of pivot of the latter with bracket 192, and isin position to be engaged by permanent magnet 180 as the latter isreciprocated with work shaft 36. A line 200 electrically couples lead172 with fixed contact 186. Inasmuch as the primary windings ofinduction coil 168 are grounded to enclosure 42, as previouslyexplained; a closed circuit may be traced from the primary windingsthrough lead 172, line 200, fixed contact 186, projection 196 of movablecontact 190, bracket 192, to enclosure 42.

' End 46 of compressor unit 12 is provided with an annular groove 202which, in turn is in fluid communication with a conduit 204 shownfragmentarily in FIGS. 1 and 2, which is adapted to be coupled with asource of fluid to be compressed. The fluid from such source is presumedto be at a relatively low pressure and may be a component of a closedrefrigerating system or the like. Groove 202 extends through the innersurface -of end 46 and communicates with the interior of drum .40,.Thus, groove 202 comprises fluid-conductor means for.conveying thefluid from conduit 204 to the interior of drum 40.

An annular plate valve 206 is positioned within drum 40 in surroundingrelationship with work shaft 36 and is held in covering relationship togroove 202 adjacent the inner surface of end 46 by spring clips 208.Valve 206 is thus positioned to prevent the flow of fluid from withindrum 40, outwardly into groove 202 and conduit 6 204, but clips 208 areyieldable to permit the flow of fluid in the opposite direction intodrum 40.

Member 38' is provided with a plurality of transversely extending holes210 communicating that portion of the interior of drum 40 above member38 with that portion below the latter. An annular valve plate 212,having a center section 214 secured on work shaft 36 by nut 216 or thelike, and outwardly radiating spokes (not shown), is held in closingrelationship to holes 210 adjacent the undersurface of member 38. Theresiliency of the spokes of plate 212, permits the latter to be shiftedaway from member 38 under the force of fluid pressure acting on theupper surface of plate 212 to permit the flow of fluid through holes 210when member 38 is shifted upwardly against fluid contained within theupper portion of drum 40. Conversely, on the downward stroke of member38, the force of fluid within the lower portion of drum 40, actingagainst the undersurface of plate 212, holds the latter securely againstthe undersurface of member 38 to prevent flow of fluid through holes210.

The bottom of drum 40 is provided with a plurality of holes 218 whichare normally closed by an annular plate valve 220 held in place adjacentthe undersurface of the bottom of drum 40 by spring clips 222. It willbe readily understood that plate valve 220 will permit the flow of fluiddownwardly from within drum 40, but will not permit fluid to enter drum40 from the bottom. Outlet means 224 which may comprise a pan 226disposed beneath the bottom of drum 40, and a pipe 228 in fluidcommunication with pan 226 and shown fragmentarily in FIG. 2, is adaptedto be coupled with a receptacle for receiving the fluid to be compressedby unit 12 which may be components of a refrigerating system or thelike.

A passage 230 extends between compartment 44 and groove 202 in end 46. Avalve 232 biased into closing relationship with passage 230 by spring234, prevents the flow of fluid from groove 202 into compartment 44.However, valve 232 may be shifted downwardly against the bias of spring234 as by suction on the outer face of valve 232, to permit fluid whichmay be within compartment 44 to be drawn into groove 202. To this end,valve 232 is of frusto-conical configuration and is complementallyengaged on a valve seat around the rim of passage 230.

In operation, engine 14 is started by manually depressing switch 156 tomake electrical connection with motor 96 and the electrically responsiveinduction apparatus 142. The energizing of motor 96 causes thereciprocation of piston by the eccentric 92. Piston 90 is thus caused topump fuel which is Within tank 76 at all times, downwardly against valve82 and cause the latter to open against the bias of spring 84, therebyadmitting fuel into combustion chamber 18 of engine 14. Simultaneouslywith the energizing of motor 96, apparatus 142 is energized, andelectrical current flows through the primary windings of induction coil168 from the circuit previously outlined. This current causes themagnetizing of core 176 which attracts extension 174, thus separatingcontacts 150 and 146. When contacts 150 and 146 are separated, thecurrent through the primary windings of coil 168 is shut off through thebreaking of the circuit and core 176 is de-magnetized. Thus, extension174 is permitted to return to a position wherein contacts 146 and 150are again engaged, resulting in magnetizing of core 176. Thismaking-and-breaking of the induction coil circuit is automaticallyrepeated as is quite conventional, so long as switch 156 is closed. Themaking-and-breaking of the circuit in the primary windings of coil 168,induces a current in the secondary windings of coil 168 which isconveyed to spark plug by Wire 178 to cause the igniting of the fuelwithin chamber 18 in the well-known, conventional manner for internalcombustion engines.

As' the fuel within chamber 18 explodes, piston 20 is driven downwardlyin cylinder 16. As piston 20 is driven downwardly, the air trappedwithin cylinder 16 beneath piston 20 is compressed. Check valve 126remains closed and prevents escape of air from extension 124. Skirt 28,depending downwardly from piston 20, covers exhaust port 30 during thisphase of the reciprocation of piston 20 and prevents the escape of airtherethrough. After piston 20 has been forced downwardly a predetermineddistance, port 30 is uncovered by piston 20, as is port 134 of airpassage 130'. This permits the air in cylinder 16 to pass throughpassage 130, port 134, through combustion chamber 18, and out exhaustport 30 to scavenge the products of combustion from chamber 18.

Inasmuch as second piston 60 reciprocates downwardly on shaft 36 withpiston 30, the air that is within second cylinder 52 beneath piston 60is forced into cylinder 16 through conduit 136, thereby increasing thevolume of air which is forced into combustion chamber 18 through passage130 when piston 20 uncovers port 134-. Such passage of air from beneathpiston 60 additionally performs the function of preventing the build-upof air pressure within cylinder 52 which occurs in conventional bouncecylinders in some forms of free-piston engines. Such air pressurebuild-up is undesirable inasmuch as it presents difficult fluid sealingproblems.

As second piston 60 moves downwardly on the combustion stroke, checkvalve 70 in extension 68 which is coupled to the source of fuel, opensto admit fuel which is sucked into cavity 56' of cylinder 52. Afterpiston 20 reaches its bottom position, it is urged upwardly under thebias of spring 100, check valve 7 then closes, and the fuel which wasdrawn into cavity 56 on the down stroke, is then forced upwardly throughpassage 72 and conduit 74 into tank 76. Whenever the pressure within thetank 76 is increased to a predetermined amount, calculated to correspondwith a certain position of piston 20 within cylinder 16, the bias ofspring 84 is overcome by the fuel pressure and valve 82 opens to admit acharge of fuel into combustion chamber 18. Thus, the automaticintroduction of fuel into chamber 18 obviates the necessity forcontinued operation of piston 90 by motor 86, and switch 156 may bereleased after the initial stroke.

The upward movement of piston 20 and work shaft 36 carries permanentmagnet 180 past core 176, thereby inducing a current in the primarywindings of induction coil 1168 as is well known. When piston 20 hasreached a predetermined position and it is desired to have the fuelwithin combustion chamber 18 ignited, permanent magnet 180 contactsmovable contact 180 of breaker mechanism 184 to break the flow ofcurrent within the primary windings of coil 168; Such breaking inducesthe current in the secondary windings of coil 168 and such current iscarried to spark plug 140 by wire 178 to effect igniting of the fuel.Thus, engine 14 operates automatically after initial starting, and it isnot necessary for continued operation of the make-and-break mechanism toeffect firing of the spark plug 140.

I Member 38 is reciprocated with work shaft 36 during cycling of engine14, and on the downward stroke of member 38, whatever fluid is containedbelow the latter is compressed until suflicient pressure is generatedwithin drum 40 to overcome the bias of spring clips 222 and permit platevalve 220 to open to admit fluid to pass through holes 218 in the bottomof drum 40 and into outlet means 224. The pressure of the fluid inoutlet means 224 against plate 220, merely serves to hold the lattermore firmly in place in covering relationship to holes 218 and precludesthe flow of fluid from the outlet to the drum. Additionally, downwardmovement of member 38 causes plate valve 206 to be shifted .away fromgroove 202 and permit the sucking of fluid from conduit 204 into drum40; As member 38 is reciprocated upwardly, the fluid passes throughholes 210 and past valve plate 212 into position to be compressed on thenext succeeding downward stroke of member 38.

Previous attempts to provide free-piston engine compressor assemblieshave not been generally successful, inasmuch as no effective means hasbeen provided to prevent the escape of fluid from the system during thecompressing operation. If the assembly is utilized in a refrigeratingsystem, the Freon gases and the like utilized for such systems, arequite expensive. The leaking of the fluid from the system duringcompressing, not only results in increased operator attention andmaintenance on the assembly, but further results in substantialeconomical loss from the necessity for replacing the refrigeratinggases.

Inasmuch as enclosure 42 is sealed to plate 24 and end 46, compartment44 is disposed to receive any fluids which leak out of drum 40 past seal50 during compressing operation. Such fluids are entrapped incompartment 44 and, inasmuch as their pressure after escape is greatlyreduced, do not have a tendency to seep past the buffer provided bycompartment 44 and into any of the other components of engine 14. Asmember 38 reciprocates downwardly within drum 40, considerable suctionis presented in groove 202 to draw the fluid to be compressed from thesource. Additionally, this suction acts upon valve 232 to unseat thelatter and permit any fluids which are entrapped within compartment 44to be re-admitted into the compressing unit.

Thus, although every attempt is made to seal against the leaking offluid past seal 50, it is recognized that inadvertent leakage will placedrum 40 in fluid communication with compartment 44. Valve 232, operableas it is by member 38, provides means for automatically returning thefluid to drum 40 for compressing. Assembly 10 then is capable ofoperating efficiently over long periods of time with substantially noloss of fluid during the compression operation.

To avoid the possibility of products of combustion, compressed air, orother fluids entering compartment 44 where they might be admitted to thecompressing unit, improved sealing means is disposed around shaft 36.Vessel 102 is kept filled with liquid at all times and provides a liquidseal permitting free reciprocation of shaft 36 without the possibilityof fluids escaping. I 'he liquid within vessel 102 provides necessarylubrication for shaft 36 and seeps along the latter to fill recess 48.Such liquid,trapped between seals 51 and 53, additionally insuresagainst the seepage of fluid from cylinder 16. With the above describedsealing precautions taken against the escape of fluid from engine 14into compartment 44, assembly 10 is assured of operation without anyproducts of combustion being admitted to a closed refrigerating systemor the like.

Although the ignition of the internal combustion engine 14 has beendescribed and explained with the use of a magneto, there is no intentionto limit the ignition to such a device. On the contrary, it will bereadily understood that other ignition devices could perform suitablyfor use with engine 14. Among these devices would be included electronicswitching systems using a transistor or a thyratron, gated radiofrequency system, or systems using a piezoelectric material as thesource of ignition energy.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. A two-cycle internal combustion engine comprising a cylinder closedat opposed ends thereof to define a chamber; a piston reciprocable insaid cylinder and having a workshaft connected thereto, one of the endsof the cylinder being provided with means clearing the workshaft;ignition means on the cylinder and extending into said chamber forigniting compressed fuel therein when. the piston is at the end of itspath of travel adjacent said opposite end of the cylinder, the side wallof the cylinder being provided with an exhaust port therein remote fromsaid opposite end of the cylinder and communicating said chamber withthe atmosphere when the piston is adjacent the opposite end of its pathof travel remote from said opposite end of the cylinder; meanscommunicating with the cylinder and operable by the piston to directsubstantially fuel-free air into the chamber to scavenge products ofcombustion from the chamber when the piston has been shifted toward saidopposite end of its path of travel to an extent to communicate thechamber with the atmosphere through said exhaust port; means coupled tothe piston for biasing the latter toward said one end of its path oftravel; and combination fuel and air delivery means operably coupledwith the cylinder for delivering alternately pressurized fuel andpressurized air to the chamber, said delivery means including a secondcylinder having closed ends defining a cavity, a second pistonreciprocable in said cavity and operably coupled with said workshaft,conduit means placing said cavity on one side of said second piston influid communication with said chamber, means for permitting flow in saidconduit means in only one direction, means communicating with said oneside of the cavity and adapted to be operably coupled with a source offuel for permitting flow of fuel into the cavity, means for precludingflow of fuel from said cavity toward the source, second conduit meanscommunicating the other side of said cavity with said air directingmeans for permitting flow of air from said directing means into saidother side of the cavity and from the cavity to said directing meansresponsive to reciprocation of said second piston in the second cylinderwhereby the quantity of air supplied by the air directing means isaugmented during reciprocation of said workshaft.

2. Apparatus as set forth in claim 1, wherein said other side of thecavity is disposed on the side of said second piston remote from thecombustion chamber so that the air in said cavity buffers the stroke ofsaid piston following ignition of said fuel.

3. Apparatus as set forth in claim 1, wherein is provided spring biasedvalve means in said fuel delivery means and between said second cylinderand the chamber for resisting the flow of fuel into the chamber untilsaid fuel reaches a predetermined pressure, whereby the introduction offuel into the chamber is correlated with the stroke of the piston.

4. Apparatus as set forth in claim 1, wherein is provided fluid sealmeans between the first and second cylinder and around the workshaft,said seal means including a liquid-containing vessel disposed in thecylinder and in surrounding relationship to said workshaft, a liquidsupply tank disposed externally of the cylinder, means placing said tankin fluid communication with said vessel, and plunger means in the tankfor forcing the liquid therefrom and into said vessel, whereby the levelof liquid in said vessel may be controlled by operation of the plungeroutside of the cylinder.

5. Apparatus as set forth in claim 4, wherein said workshaft is providedwith an internally extending channel in fluid communication with thevessel and said piston has a canal communicating with the channel andextending to the outer surface of said piston adjacent said side wallwhereby liquid is conveyed from within the vessel to said surface forlubricating the latter as the piston is reciprocated along said sidewall.

References Cited by the Examiner UNITED STATES PATENTS 976,858 11/1910Easthope 123--73 2,221,521 11/1940 Maycock 123-149 X 2,468,020 4/1949Bard 123-149 3,105,153 9/ 1963 James 123-46 X FOREIGN PATENTS 879,03610/ 1961 Great Britain.

276,900 8/ 1930 Italy.

MARK NEWMAN, Primary Examiner. W. E. BURNS, Assistant Examiner.

1. A TWO-CYCLE INTERNAL COMBUSTION ENGINE COMPRISING A CYLINDER CLOSEDAT OPPOSED ENDS THEREOF TO DEFINE A CHAMBER; A PISTON RECIPROCABLE INSAID CYLINDER AND HAVING A WORKSHAFT CONNECTED THERETO, ONE OF THE ENDSOF THE CYLINDER BEING PROVIDED WITH MEANS CLEARING THE WORKSHAFT;IGNITION MEANS ON THE CYLINDER AND EXTENDING INTO SAID CHAMBER FORIGNITING COMPRESSED FUEL THEREIN WHEN THE PISTON IS AT THE END OF ITSPATH OF TRAVEL ADJACENT SAID OPPOSITE END OF THE CYLINDER, THE SIDE WALLOF THE CYLINDER BEING PROVIDED WITH AN EXHAUST PORT THEREIN REMOTE FROMSAID OPPOSITE END OF THE CYLINDER AND COMMUNICATING SAID CHAMBER WITHTHE ATMOSPHERE WHEN THE PISTON IS ADJACENT THE OPPOSITE END OF ITS PATHOF TRAVEL REMOTE FROM SAID OPPOSITE END OF THE CYLINDER; MEANSCOMMUNICATING WITH THE CYLINDER AND OPERABLE BY THE PISTON TO DIRECTSUBSTANTIALLY FUEL-FREE AIR INTO THE CHAMBER TO SCAVENGE PRODUCTS OFCOMBUSTION FROM THE CHAMBER WHEN THE PISTON HAS BEEN SHIFTED TOWARD SAIDOPPOSITE END OF ITS PATH OF TRAVEL TO AN EXTENT TO COMMUNICATE THECHAMBER WITH THE ATMOSPHERE THROUGH SAID EXHAUST PORT; MEANS COUPLED TOTHE PISTON FOR BIASING THE LATTER TOWARD SAID ONE END OF ITS PATH OFTRAVEL; AND COMBINATION FUEL AND AIR DELIVERY MEANS OPERABLY COUPLEDWITH THE CYLINDER FOR DELIVERING ALTERNATELY PRESSURIZED